Single-cell RNA sequencing identifies a migratory keratinocyte subpopulation expressing THBS1 in epidermal wound healing

Novel monomers recipe derived from Shengji-Huayu formula targeting PI3K/Akt signaling pathway for diabetic wound healing based on accurate network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Shengji-Huayu (SJHY) formula has been used clinically for diabetic ulcer (DU) treatment. The transcriptional profiles analysis revealed the PI3K/Akt signaling pathway plays a critical role for diabetic wound healing. However, the effects and underlying mechanisms of SJHY are often challenging in diabetic wound treatment.

AIM OF THE STUDY

To explore the novel monomers recipe and mechanism of SJHY treated diabetic wound via the in vivo and in vitro experiments.

MATERIALS AND METHODS

The diabetic wound mice model was established to evaluate the therapeutic efficacy of SJHY treated diabetic ulcer. The transcriptional profile was implemented to identify the differentially expressed genes (DEGs) of SJHY treated diabetic wound mice. The constructed PPI network and KEGG-target network were used to identify the core pathway and related targets. The HPLC-MS method was used to identify the ingredients of SJHY formula. The molecular docking and in vitro experiment was used to screen which monomers regulated core pathway in diabetic wound. Finally, a novel monomers recipe was performed for diabetic wound healing.

RESULTS

The in vivo experiment demonstrated SJHY formula significantly promoted diabetic wound healing. Transcriptomic and network analysis revealed the existence of PI3K/Akt signaling pathway was high correlated with SJHY treated diabetic wound. The HPLC-MS and molecular docking revealed that Calycosin (Cal) and Dehydromiltirone (DHT) were strongly targeting Itga6 and Thbs1. The mRNA and protein levels suggested that Itga6 and Thbs1 acted as important upstream regulators of PI3K/Akt signaling pathway in diabetic wound, and the in vitro experiments revealed Cal, DHT and their recipe were significantly increased the levels of Itga6, Thbs1, PI3K and Akt in MGO induced HaCaT cells.

CONCLUSIONS

SJHY formula has therapeutic efficiency for diabetic wound healing, and Cal and DHT may be a part of the important monomers that alleviate inflammation via activating the PI3K/Akt signaling pathway by regulated Itga6 and Thbs1. Our study demonstrated Cal and DHT formed a novel monomers recipe, which may be one of the critical strategies of SJHY formula promote diabetic wound healing.

Spatiotemporal single-cell roadmap of human skin wound healing

Wound healing is vital for human health, yet the details of cellular dynamics and coordination in human wound repair remain largely unexplored. To address this, we conducted single-cell multi-omics analyses on human skin wound tissues through inflammation, proliferation, and remodeling phases of wound repair from the same individuals, monitoring the cellular and molecular dynamics of human skin wound healing at an unprecedented spatiotemporal resolution. This singular roadmap reveals the cellular architecture of the wound margin and identifies FOSL1 as a critical driver of re-epithelialization. It shows that pro-inflammatory macrophages and fibroblasts sequentially support keratinocyte migration like a relay race across different healing stages. Comparison with single-cell data from venous and diabetic foot ulcers uncovers a link between failed keratinocyte migration and impaired inflammatory response in chronic wounds. Additionally, comparing human and mouse acute wound transcriptomes underscores the indispensable value of this roadmap in bridging basic research with clinical innovations.

Mesenchymal stem cells from perinatal tissues promote diabetic wound healing via PI3K/AKT activation

BACKGROUND

Diabetic foot ulcers (DFUs) represent a major complication of diabetes, often leading to poor healing outcomes with conventional treatments. Mesenchymal stem cell (MSC) therapies have emerged as a promising alternative, given their potential to modulate various pathways involved in wound healing. This study evaluates and compares the therapeutic potential of MSCs derived from perinatal tissues-human umbilical cord MSCs (hUCMSCs), human chorionic villi MSCs (hCVMSCs), and human decidua basalis MSCs (hDCMSCs)-in a diabetic wound healing model.

METHODS

We performed in vitro and in vivo studies to compare the efficacy of hUCMSCs, hCVMSCs, and hDCMSCs. Mass spectrometry was used to analyze the secreted proteins of the MSCs. We incorporated the MSCs into a polyethylene glycol diacrylate (PEGDA) and sodium alginate (SA) hydrogel matrix with collagen I (Col-I) to evaluate their effects on wound healing.

RESULTS

All three types of MSCs promoted wound healing, with hUCMSCs and hCVMSCs showing stronger effects compared to hDCMSCs. Both hUCMSCs and hCVMSCs demonstrated robust wound healing kinetics, with enhanced keratinocyte proliferation (KRT14+/Ki67+ cells), maturation (KRT10/KRT14 ratio), and angiogenesis. In vitro studies demonstrated that the MSC-derived secretome enhanced keratinocyte proliferation and migration, endothelial cell function and stem cell recruitment, indicating robust paracrine effects. Mass spectrometry revealed a conserved set of proteins including THBS1 (thrombospondin 1), SERPINE1 (serpin family E member 1), ANXA1 (annexin A1), LOX (lysyl oxidase), and ITGB1 (integrin beta-1) which are involved in extracellular matrix (ECM) organization and wound healing, with the PI3K/AKT signaling pathway playing a central role. The PEGDA/SA/Col-I hydrogel demonstrated a unique balance of mechanical and biological properties and an optimal environment for MSC viability and function. Application of either hUCMSC- or hCVMSC-laden hydrogels resulted in accelerated wound closure, improved re-epithelialization, increased collagen deposition, and enhanced vascularization in vivo.

CONCLUSIONS

MSCs From perinatal tissues particularly hUCMSCs and hCVMSCs significantly enhance diabetic wound healing through PI3K/AKT pathway activation while hDCMSCs exhibited weaker efficacy. The PEGDA/SA/Col-I hydrogel supports MSC viability and function offering a promising scaffold for DFU treatment. These findings underscore the potential of specific perinatal MSCs and optimized hydrogel formulations in advancing diabetic wound care.

Alterations in the microenvironment of junctional epidermolysis bullosa keratinocytes: A gene expression study

Integrin α6β4 subunits and type XVII collagen are critical transmembrane proteins involved in cell-matrix adhesion in skin, while laminin 332 serves as their ligand in the basement membrane zone (BMZ). Those proteins contribute to the composition of hemidesmosomes (HDs) and pathogenic variants in their corresponding genes cause junctional epidermolysis bullosa (JEB). Although the genotype-phenotype relationships in JEB have been extensively studied, the pathogenetic changes of extracellular matrix (ECM) and cell-matrix adhesion resulting from gene mutations remain unclear. We conducted a global unbiased transcriptome analysis using bulk RNA sequencing (RNA-seq) on selected JEB donor-derived cell lines lacking integrin β4 subunit (ITGB4-), type XVII collagen (COL17-) and laminin β3 chain (LAMB3-), respectively. Additional JEB cell lines and JEB donor skin samples were used for validation of relevant findings. Collectively, the results revealed similar dysregulation patterns of ECM and focal adhesion (FAs) associated genes in ITGB4- and COL17- cell lines, while LAMB3- cells displayed a relatively opposite tendency. Importantly, key nodes in the dysregulated network were associated with ECM proteins involved in wound healing processes. Additionally, a group of inflammatory-associated genes was disclosed to be up-regulated in JEB keratinocytes and could not be normalized by the adhesion rescue. The functional assay further revealed the hierarchy of stable adhesion among mutant cell lines COL17->ITGB4->LAMB3-, which correlates with the severity of their clinical manifestations. Our results indicated a wound healing associated ECM and inflammatory microenvironment established by JEB keratinocytes.

Carboxypeptidase inhibitor Latexin (LXN) regulates intestinal organogenesis and intestinal remodeling involved in intestinal injury repair in mice

The self-renewal and regeneration of intestinal epithelium are mainly driven by intestinal stem cells resided in crypts, which are crucial for rapid recovery intestinal tissue following injury. Latexin (LXN) is a highly expressed stem cell proliferation and differentiation related gene in intestinal tissue. However, it is still ambiguous whether LXN participates in intestine regeneration by regulating intestinal stem cells (ISCs). Here, we report that LXN colocalizes with Leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5) in intestinal crypts, and deletion of LXN upregulates the expression of Lgr5 in intestinal crypts. LXN deficiency promotes the proliferation of ISCs, thereby enhances the development of intestinal organoids. Mechanically, we show that LXN deficiency enhances the expression of Lgr5 in ISCs by activating the Yes-associated protein (YAP) and wingless (Wnt) signal pathways, thus accelerating intestinal normal growth and regeneration post-injury. In summary, these findings uncover a novel function of LXN in intestinal regeneration post-injury and intestinal organogenesis, suggesting the potential role of LXN in the treatment of inflammatory bowel diseases.

Advances and applications of biomimetic biomaterials for endogenous skin regeneration

Endogenous regeneration is becoming an increasingly important strategy for wound healing as it facilitates skin's own regenerative potential for self-healing, thereby avoiding the risks of immune rejection and exogenous infection. However, currently applied biomaterials for inducing endogenous skin regeneration are simplistic in their structure and function, lacking the ability to accurately mimic the intricate tissue structure and regulate the disordered microenvironment. Novel biomimetic biomaterials with precise structure, chemical composition, and biophysical properties offer a promising avenue for achieving perfect endogenous skin regeneration. Here, we outline the recent advances in biomimetic materials induced endogenous skin regeneration from the aspects of structural and functional mimicry, physiological process regulation, and biophysical property design. Furthermore, novel techniques including in situ reprograming, flexible electronic skin, artificial intelligence, single-cell sequencing, and spatial transcriptomics, which have potential to contribute to the development of biomimetic biomaterials are highlighted. Finally, the prospects and challenges of further research and application of biomimetic biomaterials are discussed. This review provides reference to address the clinical problems of rapid and high-quality skin regeneration.

Advances in GPCR-targeted drug development in dermatology

Achieving the efficacy and specificity of G-protein-coupled receptor (GPCR) targeting-drugs in the skin remains challenging. Understanding the molecular mechanism underlying GPCR dysfunction is crucial for developing targeted therapies. Recent advances in genetic, signal transduction, and structural studies have significantly improved our understanding of cutaneous GPCR functions in both normal and pathological states. In this review, we summarize recent discoveries of pathogenic GPCRs in dermal injuries, chronic inflammatory dermatoses, cutaneous malignancies, as well as the development of potent potential drugs. We also discuss targeting of cutaneous GPCR complexes via the transient receptor potential (TRP) channel and structure elucidation, which provide new opportunities for therapeutic targeting of GPCRs involved in skin disorders. These insights are expected to lead to more effective and specific treatments for various skin conditions.

Unveiling the mechanism of high sugar diet induced advanced glycosylation end products damage skin structure via extracellular matrix-receptor interaction pathway

BACKGROUND

AGEs accumulate in the skin as a result of a high-sugar diet and play an important role in the skin aging process.

OBJECTIVES

The aim of this study was to characterize the mechanism underlying the effect of a high-sugar diet on skin aging damage at a holistic level.

METHODS

We established a high-sugar diet mouse model to compare and analyze differences in physiological indexes. The effect of a high-sugar diet on skin aging damage was analyzed by means of a transcriptome study and staining of pathological sections. Furthermore, the differences in the protein expression of AGEs and ECM components between the HSD and control groups were further verified by immunohistochemistry.

RESULTS

The skin in the HSD group mice tended toward a red, yellow, dark, and deep color. In addition, the epidermis was irregular with anomalous phenomena, the epidermis was thinned, and the dermis lost its normal structure and showed vacuolated changes. Transcriptomics results revealed significant downregulation of the ECM-receptor interaction pathway, significant upregulation of the expression of AGEs and significant downregulation of the expression levels of COLI, FN1, LM5, and TNC, among others ECM proteins and ECM receptors.

CONCLUSIONS

High-sugar diets cause skin aging damage by inducing the accumulation of AGEs, disrupting the expression of ECM proteins and their receptors, and downregulating the ECM-receptor interaction pathway, which affects cellular behavioral functions such as cell proliferation, migration, and adhesion, as well as normal skin tissue structure.

Matricellular Proteins in the Homeostasis, Regeneration, and Aging of Skin

Matricellular proteins are secreted extracellular proteins that bear no primary structural functions but play crucial roles in tissue remodeling during development, homeostasis, and aging. Despite their low expression after birth, matricellular proteins within skin compartments support the structural function of many extracellular matrix proteins, such as collagens. In this review, we summarize the function of matricellular proteins in skin stem cell niches that influence stem cells' fate and self-renewal ability. In the epidermal stem cell niche, fibulin 7 promotes epidermal stem cells' heterogeneity and fitness into old age, and the transforming growth factor-β-induced protein ig-h3 (TGFBI)-enhances epidermal stem cell growth and wound healing. In the hair follicle stem cell niche, matricellular proteins such as periostin, tenascin C, SPARC, fibulin 1, CCN2, and R-Spondin 2 and 3 modulate stem cell activity during the hair cycle and may stabilize arrector pili muscle attachment to the hair follicle during piloerections (goosebumps). In skin wound healing, matricellular proteins are upregulated, and their functions have been examined in various gain-and-loss-of-function studies. However, much remains unknown concerning whether these proteins modulate skin stem cell behavior, plasticity, or cell-cell communications during wound healing and aging, leaving a new avenue for future studies.

＜Editors' Choice＞ Supernatant from activated omentum accelerates wound healing in diabetic mice wound model

Diabetic wounds are considered one of the most frequent and severe complications of diabetes mellitus. Recently, the omentum has been used in diabetic wound healing because of its tissue repair properties. The activated omentum is richer in growth factors than the inactivated, thereby contributing to the wound healing process. To further investigate the effect of activated omentum conditioned medium (aOCM) on diabetic wound healing, we injected supernatant from aOCM, saline-OCM (sOCM), inactivated-OCM (iOCM), and medium (M) subcutaneously upon creation of a cutaneous wound healing model in diabetic mice. Wound area (%) was evaluated on days 0, 3, 5, 7, 9, 11, 14, 21, and 28 post-operation. At 9 and 28 d post-operation, skin tissue was harvested and assessed for gross observation, neovascularization, peripheral nerve fiber regeneration, and collagen deposition. We observed that aOCM enhanced the wound repair process, with significant acceleration of epidermal and collagen deposition in the surgical lesion on day 9. Additionally, aOCM displayed marked efficiency in neovascularization and peripheral nerve regeneration during wound healing. Thus, aOCM administration exerts a positive influence on the diabetic mouse model, which can be employed as a new therapy for diabetic wounds.

Targeted Single-cell Isolation of Spontaneously Escaping Live Melanoma Cells for Comparative Transcriptomics

Solid cancer cells escape the primary tumor mass by transitioning from an epithelial-like state to an invasive migratory state. As they escape, metastatic cancer cells employ interchangeable modes of invasion, transitioning between fibroblast-like mesenchymal movement to amoeboid migration, where cells display a rounded morphology and navigate the extracellular matrix in a protease-independent manner. However, the gene transcripts that orchestrate the switch between epithelial, mesenchymal, and amoeboid states remain incompletely mapped, mainly due to a lack of methodologies that allow the direct comparison of the transcriptomes of spontaneously invasive cancer cells in distinct migratory states. Here, we report a novel single-cell isolation technique that provides detailed three-dimensional data on melanoma growth and invasion, and enables the isolation of live, spontaneously invasive cancer cells with distinct morphologies and invasion parameters. Via the expression of a photoconvertible fluorescent protein, compact epithelial-like cells at the periphery of a melanoma mass, elongated cells in the process of leaving the mass, and rounded amoeboid cells invading away from the mass were tagged, isolated, and subjected to single-cell RNA sequencing. A total of 462 differentially expressed genes were identified, from which two candidate proteins were selected for further pharmacologic perturbation, yielding striking effects on tumor escape and invasion, in line with the predictions from the transcriptomics data. This work describes a novel, adaptable, and readily implementable method for the analysis of the earliest phases of tumor escape and metastasis, and its application to the identification of genes underpinning the invasiveness of malignant melanoma.

Significance

This work describes a readily implementable method that allows for the isolation of individual live tumor cells of interest for downstream analyses, and provides the single-cell transcriptomes of melanoma cells at distinct invasive states, both of which open avenues for in-depth investigations into the transcriptional regulation of the earliest phases of metastasis.

Development and characterization of ferret ex vivo tracheal injury and cell engraftment model

The field of airway biology research relies primarily on in vitro and in vivo models of disease and injury. The use of ex vivo models to study airway injury and cell-based therapies remains largely unexplored although such models have the potential to overcome certain limitations of working with live animals and may more closely replicate in vivo processes than in vitro models can. Here, we characterized a ferret ex vivo tracheal injury and cell engraftment model. We describe a protocol for whole-mount staining of cleared tracheal explants, and showed that it provides a more comprehensive structural overview of the surface airway epithelium (SAE) and submucosal glands (SMGs) than 2D sections, revealing previously underappreciated structural anatomy of tracheal innervation and vascularization. Using an ex vivo model of tracheal injury, we evaluated the injury responses in the SAE and SMGs that turned out to be consistent with published in vivo work. We used this model to assess factors that influence engraftment of transgenic cells, providing a system for optimizing cell-based therapies. Finally, we developed a novel 3D-printed reusable culture chamber that enables live imaging of tracheal explants and differentiation of engrafted cells at an air-liquid interface. These approaches promise to be useful for modeling pulmonary diseases and testing therapies. Graphical abstract1,2. We describe here a method for differential mechanical injury of ferret tracheal explants that can be used to evaluate airway injury responses ex vivo. 3. Injured explants can be cultured at ALI (using the novel tissue-transwell device on the right) and submerged long-term to evaluate tissue-autonomous regeneration responses. 4. Tracheal explants can also be used for low throughput screens of compounds to improve cell engraftment efficiency or can be seeded with particular cells to model a disease phenotype. 5. Lastly, we demonstrate that ex vivo-cultured tracheal explants can be evaluated by various molecular assays and by immunofluorescent imaging that can be performed live using our custom-designed tissue-transwell.

Research on the wound healing effect of Shengji Huayu Formula ethanol extract-derived fractions in streptozotocin-induced diabetic ulcer rats

BACKGROUND

Diabetic ulcer is a common complication of diabetes. It is characterized by a long-term disease course and high recurrence rate. Shengji Huayu Formula (SHF) is an effective formula for treating diabetic ulcers. However, the specific effective parts of SHF remain unclear. Clarifying the active polar site of SHF would be helpful to refine research on the components in SHF that promote wound healing. This research aims to focus on evaluating the activity of polar fractions.

METHODS

A diabetic rat model was established by intraperitoneally injecting streptozotocin (STZ) and was adopted to confirm the therapeutic effect of SHF. Four different polarity parts were extracted from SHF and prepared into a cream to evaluate the activity. High-performance liquid chromatography (HPLC) was used to detect chemical constituents in chloroform extracts.

RESULTS

It was discovered that dracorhodin, aloe-emodin, rhein, imperatorin, emodin, isoimperatorin, chrysophanol, physcion, and tanshinone IIA were the main components of the chloroform extract from SHF. The results revealed that chloroform extract could effectively accelerate diabetic wound healing by promoting collagen regeneration and epidermal repair. Chloroform extract of SHF could stimulate the generation of vascular endothelial growth factor (VEGF). The results are also indicated that the effective active fraction was the chloroform part, and the method of detecting the main chemical constituents in the active part was successfully established.

CONCLUSION

SHF could improve diabetic ulcers by promoting granulation tissue synthesis. In this study, four polar parts (petroleum ether, chloroform, ethylacetate, n-butanol) were extracted from a 95% ethanol extract. In contrast, chloroform polar parts showed a higher wound closure rate, stimulated more collagen regeneration and promoted more production of vascular endothelial cells. In conclusion, the chloroform extract of SHF was the effective polar part in ameliorating diabetic wound healing.

Antibody gene transfer treatment drastically improves epidermal pathology in a keratitis ichthyosis deafness syndrome model using male mice

BACKGROUND

Keratitis ichthyosis deafness (KID) syndrome is a rare disorder caused by hemichannel (HC) activating gain-of-function mutations in the GJB2 gene encoding connexin (Cx) 26, for which there is no cure, or current treatments based upon the mechanism of disease causation.

METHODS

We applied Adeno Associated Virus (AAV) mediated mAb gene transfer (AAVmAb) to treat the epidermal features of KID syndrome with a well-characterized HC blocking antibody using male mice of a murine model that replicates the skin pathology of the human disease.

FINDINGS

We demonstrate that in vivo AAVmAb treatment significantly reduced the size and thickness of KID lesions, in addition to blocking activity of mutant HCs in the epidermis in vivo. We also show that AAVmAb treatment eliminated abnormal keratinocyte proliferation and enlarged cell size, decreased apoptosis, and restored the normal distribution of keratin expression.

INTERPRETATION

Our findings reinforce the critical role played by increased HC activity in the skin pathology associated with KID syndrome. They also underscore the clinical potential of anti-HC mAbs coupled with genetic based delivery systems for treating the underlying mechanistic basis of this disorder. Inhibition of HC activity is an ideal therapeutic target in KID syndrome, and the genetic delivery of mAbs targeted against mutant HCs could form the basis of new therapeutic interventions to treat this incurable disease.

FUNDING

Fondazione Telethon grant GGP19148 and University of Padova grant Prot. BIRD187130 to FM; Foundation for Ichthyosis and Related Skin Types (FIRST) and National Institutes of Health grant EY 026911 to TWW.

An optimized protocol to identify keratinocyte subpopulations in vitro by single-cell RNA sequencing analysis

Here, we describe a protocol for single-cell isolation from the primary culture of normal human epidermal keratinocytes derived from neonatal foreskin. The cell culture conditions have been optimized for inducing expression of keratinocyte differentiation markers. Cells are cultured in the absence or presence of a bioactive lipid lysophosphatidic acid (LPA). Single cells are isolated by Fluidigm C1 system. This is followed by cDNA library preparation using Takara SMART-Seq v4 Ultra and Illumina Nextera XT kit for RNA sequencing. For complete details on the use and execution of this protocol, please refer to Siriwach et al. (2022).¹.

Matricellular proteins in cutaneous wound healing

Cutaneous wound healing is a complex process that encompasses alterations in all aspects of the skin including the extracellular matrix (ECM). ECM consist of large structural proteins such as collagens and elastin as well as smaller proteins with mainly regulative properties called matricellular proteins. Matricellular proteins bind to structural proteins and their functions include but are not limited to interaction with cell surface receptors, cytokines, or protease and evoking a cellular response. The signaling initiated by matricellular proteins modulates differentiation and proliferation of cells having an impact on the tissue regeneration. In this review we give an overview of the matricellular proteins that have been found to be involved in cutaneous wound healing and summarize the information known to date about their functions in this process.